Explosively actuated tools



July 26, 1960 R. J. KOPF ETAI- EXPLOSIVELY ACTUATED TOOLS Original FiledMay 14, 1953 6 Sheets-Sheet 1 July 25, 1950 R. J. KOPF ETAL h 2,946,061

EXPLOSIVELY ACTUTED TOOLS 6 Sheets-Sheet 2 Original Filed May 14, 1953MMO y o n 5 ro N NK. R WJH www M wm b XX By Hoger Manr/v July 26, 1960R. J. KOPF ETAL 2,946,061

EXPLOSIVELY ACTUATED TOOLS Original Filed May 14. 1953 6 Sheets-Sheet 38 5/ f4 528/6066 7g-I /Jo BY Ho er Mars/1 R. J. KOPF ETAL EXPLOSIVELYACTUATED TOOLS July 26, 1,960

6 Sheets-Sheet 4 Original Filed May 14. 1953 July 26, 1960 R. J. KOPFETAL EXPLOSIVELY ACTUATED TOOLS Original Filed May 14', 1953 6Sheets-Sheet 5 l July 26, 1960 R. J. KOPF ETAL EXPLOSIVELY ACTUATEDTOOLS Original Filed May 14. 1953 6 Sheets-Sheet 6 zal Robe/" WHenn/'lig BY Hager Mahr/r Y v 2,946,061 j Patented July ze, 1960nXPLosIvELY ACTUATED TooLs Rowland J. Kopf and Robert W. Henning, RockyRiver, and Roger Marsh, Hudson, hio, assgnors to Olin Mathieson ChemicalCorporation, a corporation of Virginia Original application May 14,1953, Ser. No. 355,034.

Divided and this application Jan. 7, 1959, Ser. No. 796,999

4 Claims. (Cl. 1-9-106) This invention relates to improvements in afastener driving tool and more particularly to a tool of the powderactuated type. This application is a division of co-pending applicationSerial No. 355,034, led M-ay 14, 1953.

The object of the present invention is to provide a powder actuatedfastener driving tool characterized by its structural simplicity, theeconomy of its manufacture, ease of assembly of its parts, its operatingefficiency, its many safety features, its ease of operation, and itsuniversal construction for use under many different conditions.

Other features of this invention reside in the arrangement and design ofthe parts for carrying out their appropriate functions. Other objectsand advantages of this invention will be apparent from the accompanyingdrawings and description and the essential features will be set forth inthe appended claims.

In the drawings,

Fig. 1 is a Vertical, longitudinal, sectional view of the powderactuated tool in the safety or normal position;

Fig. 2 is a side elevational view of the tool in Fig. 1

'partly in vertical longitudinal section with the barrel muzzle `andtool pressed against the workpiece on the left with the tool in thereadytolire position;

Fig. 3 is a vertical, transverse sectional view taken along the line 3 3in Fig. l through the ring pin, pawl, and trigger of the powder chargefiring means;

Fig. 4 is a vertical, transverse sectional view taken along the line 4-4of Fig. l through the breech block and front of the trigger guard;

Fig; 5 is a vertical, transverse sectional view taken along the line 5-5of Fig. l through the screw coupling between the breech block and barrelwhen the tool is fully locked;

Fig. 6 is a vertical, transverse sectional View taken along the line 6-6of Fig. l through the rear of the extension rod unit with a portion o-fthe housing surrounding the barrel broken away to expose an interlockpin;

Fig. 7 is `a longitudinal, radially extending, sectional view takenalong the line 7-7 of Fig. 6 through the interlock pin and barrel guidescrew;

Fig. 8 is a vertical, transverse sectional view taken along the linel8-8 of Fig. 7 to disclose the locking action ,of the interlock pin; y

Figs. 9 and 10 are side elevational views of the tool respectively withits assemblies screwed together for ring and pivoted `open for loading;

Fig. 11 is a vertical, transverse sectional view taken along the line11--11 in Fig. l through the spring loaded extension rod release buttonand the deector pad, ilash shield telescopic mounting in the toolhousing;

Fig. 12 is a vertical, transverse sectional view taken along the line12-12 in Fig. 1 looking toward the ilash shield; Y

Fig. 13 is a sectional View taken along the line 13-13 f of Fig. 6 ofthe barrel guide slot in the outside surface of the barrel with thebarrel guide screw in section coacting therewith;

2 Fig. 14 is a side elevational view of the tool after an unsuccessfulattempthas been made to iire it while the barrel axis was tilted asubstantial amount with respect to the normal to the workpiece surface;

. Fig. 15 is a side elevational view, partially in section, of the toolin a ready-to-re position corresponding to Fig.

2 but having a barrel `extension and the extension rod in' use;

Fig. 16 is a longitudinal, vertical section view throughy a modifiedform of detachableconnection at the tool- Y lbreech with this viewgenerally corresponding to the breech portion of Fig. 1;

Fig. 17 is a vertical transverse sectional view taken`l along the line17-17 of Fig. 16 and generally corresponding to Fig. 8;

Fig. 18' is a vertical, longitudinal section taken` through theextension rod and its spring biased release button cor responding to aportion on the left of Fig. 1 but with the extension rod in Fig. 18having buttress form threads as a modification; while Y Fig. 19 is avertical, transverse sectional view taken along the line 19-19 of Fig.18 and generally corresponding to the lower half vof Fig. 11.

Y Before the tool here illustrated is specifically described, it is tobe understood that the invention here involved is not limited` to thestructural details or arrangement of parts here shown since toolsembodying the present invention may take various forms. It also is to beunderstood that the phraseology or terminology herein eml ployed is forpurposes of description and not of limitation since the scope of thepresent invention is denoted by the appended claims.

Those familiar with this `art will recognize that the present inventionmay be applied in many lways, but it.' has been chosen toillustrate thesame `as a' powder actu` ated, fastener driving tool. Many of thefeatures may be used on other tools, other powder charge actuateddevices, and other projectile or fastener firing or driving devices.

The tool is illustrated in general in Fig. 1. It comprisesinterconnected pistol grip or handle 20, barrel 2,2,

and a powder charge tiring means 28. The -tool can be' divided into twomajor parts, the -barrel assembly 18 and the breech assembly 19, shownin Fig. l generally on the` left and right of section line 5--5respectively and in` Fig. 4l0 on the left and right respectively.The'barrel assembly 18 has a barrel 22 with a chamber in itsbreechlfor'receiving a lfastener unit comprising in Fig. 2 a carv tridgecase-23a with a primer and powder charge and a fastener 23b so that thefastener will ybe driven through the ybarrel bore when the primer isstruck to explode the powder charge. The breech assembly 19 has a powdercharge firing means, generally shown at 28 in Fig. 1 and including afiring pin for striking said primer and a trigger Iforrelease ofthefir-ing pin. The tool has a housing 21 surrounding the barrel 22 and thetiring means i 28 with the barrel 22 mounted yfor telescopic endwiseor,V axial movement in and relative to the housing between a V normal,muzzle advanced, safety, first position in Fig. 1 and a muzzledepressed, ready-to-iire or Ytiring, second position in Fig. 2. The toolis movedrendwise between` the rst and second positions by pressing thebarrel muzzle Iagainst Vthe workpiece 25 on the left in Fig. 2 intowhich the fastener 23b is tobe driven and then. telescopically movingthe tool housing 21 over the barrel 22. I-t should -be noted'that `thebarrel breech and the tiring means 28 in the rst and second positionsare re-` spectively spaced widely apart and adjacent each other" whilethe housing 21 moves endwise in traveling relative to the barrel fromthe rst to the second position. As `will be brought out in further`detail hereinafter, this endwise movement ofthe tool housing 21 relativeto the barrel from the lirst to the second position cocks the firing pinfor release by the trigger in the firing means 28.

The muzzle of the tool also includes a flash shield 24 in Fig. =l biasedtoward the left by spring 26 so as to firmly engage the workpiece 25 inFig. 2 to protect the tool operator from ricochets and spalling of theworkpiece 25.

The barrel assembly 18 in Fig. 1 has barrel 22 surrounded by a firstportion of the tool housing 21 hereinafter called ban'el housing 50. Thebreech member or assembly 19 has the powder charge tiring means 28surrounded by the second portion of the housing 21 hereinafter calledbreech housing 27. This latter housing portion comprises a one-piecereceiver housing 20a, hand grip 20 and trigger guard 20b and alsoincludes a firing mechanism housing 30 inserted into the cylindricalbore of the receiver housing 20a and held therein by a screw 31.

A firing pin 34 in Fig. 1 travels in the bore of the firing mechanismhousing 30 and is resiliently biased by a firing pin spring 35 to movetoward the left in Fig. 1 toward the barrel in the general axialdirection of the barrel bore. The firing pin spring 35 is capturedbetween the tiring pin bore and in the tiring mechanism housing 30 andan aligned bore in the receiver housing 20a so that the firing pin isnormally urged to the left in Fig. 1 until it encounters the shoulder36a of its surrounding bore.

A breech lblock 37 in Figs. 1 and 4 is mounted for relative axialmovement but no rotation`al movement relative to its surrounding housing27 in the bore extending inwardly from the left into tiring mechanismhousing 30. A breech block screw 39 has its head traveling in an axiallyextending slot 30h of the firing mechanism housing 30 so that relativeaxial movement but no rotational movement can take place. The housing 30is movable axially relative to not only the barrel 22 but also thebreech block 37 between the normal, iirst or safety position (Fig. 1)and a ready-to-fire position (Fig. 2), in the latter position, thebreech block 37 being located closer to the rear of the housing 27. Afiring mechanism spring 38 biases the breech block 37 toward the left inFig. 1 so that the breech block will always be normally in the safetyposition advanced toward the left for detachable connection over thechamber of the barrel. Both springs 26 and 38 normally urge the barreland the breech block 37 toward the left in Fig. l so as to normallyassume the safety position. However, when the barrel muzzle is pressedagainst `the workpiece 25 in Fig. 2, the force of these springs isovercome so that a tiring pin pawl 42 onY the tiring pin 34 moves into contact with a cooking rod 40 on the breech block for exerting a forceagainst the pawl in the direction of ring pin cocking travel as the toolmoves from the first to the second positions respectively shown in Figs.1 and 2 so as to cock the firing pin. It should be noted that the ringpin 34 is cocked in response to the relative movement between barrel 22and the tool housing 21 from the iirst to the second position since thecocking pin 40 is fixed with respect to the barrel. The cooking of thetiring pin is entirely independent of actuation of trigger 46 pivotallymounted by a trigger pivot 47 in a slot 30e cut in the bottom of thetiring mechanism housing 30 in Figs. 1 and 3. The trigger 46 is not onlyinoperative to cock the tiring pin 34 but also normally inoperative torelease the firing pin when the tool is in the Fig. `1 position.

However, the trigger 46 is manually operable to release the tiring pin34 to strike the primer and explode the powder in the cartridge case 23awhen the tool is in the ready-to-re position of Fig. 2. As the triggeris pulled and pivots counterclockwise around the pin 47, a sear 46aonsaid trigger moves upwardly to depress the tiring pin pawl 42 in adirection at a right angle withrespect to the tiring pin travel andagainst the resilient bias of its firing pin pawl spring 43 so that thefiring pin moves free of the restraining action of cocking rod 40. Then,the

tiring pin spring 35 will drive the ring pin 34 toward the left throughthe aligned firing pin hole 37a to strike the primer of cartridge case23a.

It should be noted that the cooking rod 40, firing pin pawl 42, firingpin 34 and tiring pin hole 37a always keep in correct alignment becausethe breech block 37 cannot rotate since its guide screw 39 travels onlylongitudinally in slot 30h of the firing mechanism housing 30 and sincecocking rod 4G, the trigger 46 and the tiring pin pawl 43 all travelwithin the restraining side walls of slot 30a` of the firing mechanismhousing 30, as seen in Figs. 1, 2 and 3, to prevent rotation of theseparts relative to hous- V ing 30.

After the trigger 46 has been released, the trigger return spring 49,bearing against the rear edge of the trigger rotates it clockwise to theFig. 1 position, so that the pawl 42 can be pushed without interferenceto a position above it, corresponding to Fig. 2, when the tool is usedagain. The trigger spring 49 is of T-shape with an upper cross barthereon vertically inserted up into a pair of slots straddling the slots30C in the bottom of the firing mechanism housing in dotted lines inFig. 3.

Although springs 26 and 38 normally urge barrel 22 to the Fig. l safetyposition, firing pin spring 35 also urges it toward the left and a safeposition through interconnected pawl 42 and rod 40 to assure that tiringpin 34 will be safely spaced from cartridge case 23a.

Although the breech assembly 19 includes an interconnected breech block37, tiring pin 34, trigger 46 and handle or pistol grip Z0 extendinglaterally from the bore axis of the barrel member, the parts arespecically constructed for rapid and convenient assembly. It breaks downinto two units. A rst unit comprising the integrally formed receiverhousing 20a, hand grip 20 and trigger guard 2Gb having an opening in thereceiver housing from the front thereof (from the left in Fig. l). Thefront of the trigger guard, instead of being solid as a conventionaltrigger guard, is divided into two arms by a downwardly protruding slot20c in Figs. l and 4 having an open front and an open top communicatingwith the cylindrical bore in the front of the integral member forsurrounding the tiring mechanism housing 30. The second unit comprises afiring mechanism with the firing mechanism housing 30, firing pin 34,tiring pin spring 35, breech block 37, tiring mechanism spring 38,breech block screw 39, cooking rod 40, firing pin pawi 42, tiring pinpawl spring 43, trigger 46, trigger pivot pin 47, and trigger returnspring 49. This second unit, including the aforesaid respective parts,is telescoped rearwardly during assembly into the cylindrical bore inthe front of the receiver housing 20a. Since the downwardly extendingtrigger 46 and trigger return spring 49 are less in width (Fig. 4) thanthe slot 20c in the front of the trigger guard, this second unit can betelescoped rearwardly as a unit and then can be secured in position bythe screw 31. It should be noted that the tiring pin spring 35 is housedin aligned bores in the receiver housing 20a and tiring mechanismhousing 30. This two unit construction permits the entire second unit tobe assembled within the firing mechanism housing 30 before assembly intothe receiver housing 26a since the trigger and its return spring arenarrow enough to pass through the slot 20c during assembly.

The barrel assembly 18 includes the barrel 22 surrounded by barrelhousing 50, as` mentioned before. A screw 53 secures an outer tubecollar 51, telescopically mounted over the barrel, within an outertube54 and also secures a hinge bracket 52 to the outer surface of theouter tube 54. The barrel housing 5G.comp rises collar 51 and tube 54.

The chamber of the barrel 22, located at the` breech, has a detachablebreech plug 56 insertable into or removable romsaid chamber duringloading and unloading with the bore of said plug adapted to receive-,a

tween the tool assemblies 18 and 19 so that these assem-v blies can bedetachably secured together, the tool either assuming the Fig. 1 andFig. 9 locked relationship or unlocked, detached and swung to the Fig.10 position for loading and unloading. The breech block 37 has atelescopic connection iitting over the breech of barrel member 22 withmating screw threads 37: and 22t respectively in Figs. l, 5, 10 and 13extending along an axis in the same general direction as the barrelbore. However, as seen on the barrel member 22 in Fig. 13, the threadsextend only for a short arcuate length and the same correspondingarcuate length and spacing exists on the lbreech block 37 so that themating threads 37t on the breech block may be telescoped throughthe gapbetween the threads 22t on barrel member 22 until the tool issubstantially closed and then only one-eighth turn is necessary to fullylock or unlock the tool. The threads 22! and 37! are shown incircumferential registration with 4the tool in fully locked position inlFig. 5. The threads on the barrel member 22 and the breech block 37 areeach arranged in four equal width sector shaped thread groups equallycircumferentially Vspaced with the spacing between each group largerthan the width ofany thread group of both threads 22t and 37t foradequate clearance during the telescopic action.

Connecting means are provided between the barrel assembly 18 and thebreech assembly 19 for pivotal,

axialv and rotative relative movement between these twoA This includes ahinge ring 58 in Figs.V

tool assemblies. 1 and 5 positioned between spaced shoulders on thefront of the receiver housing 20a and on the tiring mechanismY housing30 to provide an annular groove to rotate ring 58 relative to the handgrip 20. A register pin 59 in lFig. 5 is driven into and secured withina hole in hinge ring 58 so as to travel in a 45 arcuate slot 30d in thetiring housing mechanism 30 to provide the one-eighth relative turningaction necessary for locking or unlocking the tool. A pivot hinge isprovided by downwardly extending ears on the hinge ring 58 in Fig. 5coacting with rearwardly extending spaced ears on the hinge bracket 52.Each ear on the hinge ring 58 has an elongated slot therein, as shown inFig. 1, so as to make possible the axial or telescopic action. Hingescrew 61 is screwed into threaded holes in the ears of the hinge bracket52 while freely traveling in these elongated slots. A locking nut 62 isprovided on the screw 61 to firmly lock the assembly together.

This construction permitsassemblies 18 and 19 to move from the lockedposition in Figs. 1 and 5 to an unlocked and disassembled position. Theassemblies 18 and 19 rotate relative to each other in moving betweenthese positions. Barrel assembly 18 carries non-rotatively therewithbarrel 22, hinge bracket ears 52, screw 61, hinge ring 58 and registerpin 59. Hence, during relative ro' tation of the assemblies between saidpositions, the ring 58 rotates in its groove in breech assembly19.v Theaxial movement of the assemblies 18 and 19 is permitted by the elongatedslot in each ear on hinge ring 58 in Fig. 1 while the pivotal movementis permitted by the hinge connection provided by screw 61, the ears onhinge ring 58, and the ears on hinge bracket 52.

Means is also provided for securing together at the breech the housingportions 27 and S0 in both assemblies 18 and 19. Firing mechanismhousing 30 has at its forward end two diametrically spaced over-latchingpins 63, 63 in Fig. `1 with each pin driven through a hole therein, asshown 'in Fig. 8, with the inner edge of each pin extending into thebore of tiring mechanism 30 that telescopes over the outer tubecollar51. The outer tube collar 51 has diametrically aligned flats 51a, oneofwhich being shown in Fig. 8, on its peripheral surface so that each pin63 can telescope over its associated Ilat 51a as the breech block 37telescopes over"v the`brech of the `barrel 22. Then, when thel breechlblock is turned one-eighth turn with respect to the bar-y rel to lockthe threads22t and 37t together, both overlatching pins 63, 63 arerotated into the groove 51b in Figs. 1, 7 and 8 in the outer surface ofthe outer tube collar V51st) as to lock the assemblies. and housingstogether Hence, it is readily seen that the tool` assemblies 18 and 19`can be moved to either the assembled relationship in Fig. 9 for firingor the disassembled relationship in Fig. l0 for loading and unloading.The tool is so constructed so that if the surface upon which the opentool is rested, which may be the surface` of the workpiece 25, isapproximately horizontal, as shown in Figs. 9 and l0, the tool willremain upright when the assemblies are either screwed together forfiring, as shown in Fig. 9, or pivoted open for loading or unloading, asshown in Fig. 10, because the shield 24 has a surface engagement portionalong its periphery located a sucient distance from the barrel axis andall the parts of the tool to prevent tipping. It should be noted thatthe relative pivotal and rotational movements of the breech assembly 19,because of the -arrangement of the hinge pin 61 transverse to the axisof the barrel bore and the travel of register pin 59 in the arcuate slot30d in Fig. 5, is such that the assembly is laterally swingable towardthe barrel assembly 18l to bring the center of gravity of the tool wellwithin the periphery of the shield and nearer the Yshield despite thelateral offset of the tool center of mass. Fig. 10 illustrates thebreech assembly 19 in this inwardly swung position. Hence, the tool willstand upright on any flat horizontal surface to provide greaterconvenience in loading and unloading, easier disposal of the toolbetween shots or series of shots, a better appearance, and easieroperation because it does not tend to -fall over despite being bumpedand does not have to be frequently lifted and reoriented.

After the breech plug 56 has been removed from the barrel chamber, thefired cartridge case must be ejected from itsbore. An ejector rod ispreferably pro-vided on the tool in any convenient place for thispurpose, but two different types are illustrated in Fig. 10. First,l arod 61a in Figs. 5 and'lO is formed integral with and projects from thehinge screw or pivot pin 61. Second, a rod 65 is formed integral with alocking screw on the ash shield 24. Both rods have a diameter less thanthe breech plug bore and are sufficiently long so that when the breechplug 56 is removed from the barrel chamber after tiring and telescopedover said rod, the spent cartridge case 23a will be ejected from thebore.

' It should be noted that the workpiece 25 always'backs up both rods 61aand 65 to serve as a rm base for the ejecting action since both rodsextend generally perpendicular to the workpiece surface or generally inthe same direction as the barrel bore. The jam or lock nut 62 in Fig. 5on the hinge screw 61 can be tightened to assure that rod 61a will'beretained at the most convenient angle for operator use. With either rod61a or rod 65, the number of parts in the tool is reduced since each isformed integral with another necessaryV tool element. Also, the locationof rod 61a immediately adjacent to the barrel chamber is especiallyconvenient.

The tool is easily `and readily loaded and unloaded. To open the to'ol,the operator grasps the barrel housing 50 of the barrel assembly 18 inone hand while grasping the handle 20 in the other. Then, the handle 20is rotated one-eighth turn counterclockwise as viewed from the hand grip20 looking toward the shield 24. 1 The .dle 20 is pvoted about hinge pin61 and is rotated until"`l Each rod is located forl usersconvenience'.Vv

it rests against the barrel assembly 18 to assume the Fig.` l position'.The operator removes the breech plugV 56 from the barrel chamber andtelescopes it. over either rod 61a or rod 65 in Fig. l0Y to eject thespent cartridge case 23a. Then, fastener 23b (Fig. 2) is inserted pointrst into the barrel bore through the breech and a new cartridge case 23ais inserted into'` the bore of the breech plug 56 after which the breechplug is inserted into` the barrel chamber. The tool is locked or closedby grasping the outer surface of the barrel assembly 18 in one hand andthe hand grip 20 in the other and then reversing the opening orunlocking procedure in swinging, telescoping and rotating through a,one-eighth turn the breech assembly 19.

As mentioned before, after the tool assemblies are locked closed in theFig. l position, the tool housing 21 must be telescoped to the left overthe barrel 22 to cock the ring pin by moving the tool from the first,normal or safety position in Fig. l to theready-to-iire or secondposition in Fig. 2. Although during this movement the tube collar S1must telescope over the barrel 22 in Fig. l, there must be very littlerelative rotation therebetween or else the screw threads 22! and 371 onthe barrel breech and the breech block 37 respectively may unscrew anddangerously open the breech during tiring. The screw 53 in Figs. 1 Vand13 is used not only to assemble the parts but also as a barrel guidescrew by coacting with the slots 22a, 22b. Hence, the outer tube collar51 can bel moved endwise or axially in a telescopic manner over barrel22 but will not appreciably rotate relative thereto. The slot has awidened portion 22b for cooperation with the barrel guide screw 53 whenthe tool approaches and is in the ready-tore position of Fig. 2 so as toprevent turn jamming the barrel in the ready-to-fire position. The end22a of the slot is of minimum width` to guide the barrel guide screw 53so as to minimize rotation of the barrel 22 relative to its surroundingbarrel housing 50. If this narrow width were carried the full length ofthe slot or groove, necessary minimum rotation of the other parts of thetool required for clearance and ease of operation might permit the tooloperator, by twisting the tool component parts relative to each otherafter the tool was depressed against the workpiece in the Fig. 2position, to bind the side of I'groove or slot 22a4 against the barrelguide screw 53 by turn jamming to jam the barrel in the Fig. 2 positionfor so called air firing. Then, the tool could be removed from theworkpiece, while keepingthe tool parts bound in the Fig. 2 position, soas to fire the fastener like a gun driven projectile into the air by airfiring instead of into the workpiece. If turn jamming could occur, thetool` could be fired in the same manner as a gun with` fastener 23bbeing dangerously used as a projectile. This firing could occur eventhough the barrel muzzle was not pushed-up against a workpiece 25 sinceany turn jamming would prevent the barrel 22 traveling forwardly to itsFig. 1 safety position under the bias of springs 26 and 38 upon removalof the tool from the workpiece. The groove end 22b is thus widened sothat once the tool is locked and brought to the ready-tore position inFig. 2, the barrel guide screw 53 is in the Wide portion of the guidegroove to prevent turn jamming.

After the one-eighth turn locking action has taken place so that thetool is locked in the Figs. 1 and 5 position, and the housing 21.ismoving to the left over the barrel 22 from the Fig. l safety to the Fig.2 ready-tore position, an interlock means .on the housing 21 isresponsive to the movement `of the housing 21 relative to the barrelapproaching said ready-to-re position for locking the breech block 37and the whole breech assembly 19 against detachment from the barrel 22andbarrel assembly 18 during, ring. Figs. 6, 7 and 8 disclose aninterlock pin 66 of-generally L-shape having its short` legs traveling.Vabovea tlat 22C on the barrel while the remainder of the pin slides in athrough radial slot 51e in the outer tube collar 51 and a peripheralslot 51d also therein with both of these slots generally extending in aninterlock pin 66 movable in the barrel axis direc tion. Fig. 7 disclosesthe interlock pin 66 in the un locked position in solid lines when thetool is in the Fig. 1 position and discloses the interlock pin in lockedposition in dot-dash'lines when the tool is in the ready-tore Fig. 2position since the shoulder at the left end of at 22e pushes against thevertical leg of the interlock pin 66 to move it to the dot-dash lineposition. In the dotdash line or locked position, the horizontal leg ofthe interlock pin 66 travels axially to the right in Fig. 7 back intothe cutout formed by the bore in the tiring mechanism housing 30 pastthe overlatch pin 63 so that the assemblies cannot become fullyunscrewed. Any attempt to rotate the firing mechanism housing 30relative to the outer tube collar 51' for unscrewing the threads 22t onthe breech of the barrel would be prevented because the overlatch pin 63in Fig. 8 cannot rotate out of the peripheral groove Slb onto theclearance flat 51a for removal since the interlock pin 66 blocks itstravel.

It should also be noted that if the assemblies are not fully screwedtogether when the breech assembly 19 has been turned relative to thebarrel assembly 18, movement of the tool from the Fig. l toward the Fig.2 position will be blocked for safety purposes when interlock pin 66abuts against the shoulder in the bore formed by the overlatch pin 63 inFig. 8 and thus prevent the tool from attaining the ready-to-fireposition of Fig. 2. I It should be also noted that interlock pin 66 isunlocked 1n response to the movement of the tool away from the Fig. 2ready-to-re position since the shoulder on the right .end of the barrelflat 22e engages the vertical leg of the interlock pin 66 to pull itfrom the dot-dash to the solid line position in Fig. 7. When theinterlock pin 66 is in the dot-dash line position in Fig. 7, it ispossible for the tooly operator, by relatively twisting the toolassemblies 18 and 19 toward their unlocked position, to bind the lockpin 66 in this position against the side of its mounting slot in collar51. However, the barrel 22 is free to move a substantial distance towardthe Fig. l or safety position as soon as the barrel muzzle is removedfrom the workpiece even though the interlock pin 66 itself may bejammed, because the flat 22e` between its end shoulders is ofsubstantial length to serve as a lost motion movement transmitting meansbetween barrel and pin and because springs 26 and 38 will bias thebarrel toward the safety position.

This structure prevents (l) firing the tool in the unlocked position,(2) inadvertent unlocking of the tool in its ready-to-re position orfiring position, and (3) any deliberate attempt to turn jam the tool forair firing.

The timing between the barrel guide slot action and the interlock pinaction is clearly shown in Fig. 7. The interlock pin 66 is effective(moved to its dot-dash line position in Fig. 7) when the barrel guidescrew 53 reaches the wide portion 22b of the elongated barrel guide slotin Fig. 13.

Flash shield 24 and its appurtenant parts are shown in more detail atthe left in Fig. l and in Fig. l2. This flash or deector pad shield 24is telescopically mounted over the barrel 22 near its muzzle and isadapted to engage for safety purposes the workpiece 25, as shown in Fig.2,4 during driving of the fastener 23h. This shield 24 has a plate 68rotatably secured thereto by a screw 72 and nut 73 connection in thecenter of the plate 68 but laterally spaced from the bore of barrel 22.A hydrogen braze secures the plate 68 to a shield tube 70 extending awayfrom the shield 24 toward the right in Fig. 1. Both the shield 24 andthe tube 70 are telescopically mounted over the barrel 22. The shieldtube 70 telescopes through the open end on the left and intothe outertube 54 in Fig. l.

The plate 68, screw and nut connection 72, 73, and the shield'A 24 coacttogether to form an adjustable gage for axis so that pivoting the shield24 will move it eccentrically with respect to the barrel axis and theindicia and reference marks on shield 24 and plate-68 can be'used inspacing fasteners since the shield tubeV 70 is nonrotatably mounted withrespect to the barrel 22, as will be brought out in more detailhereinafter. A clamping screw 74, threaded into the shield 24, 'has ashoulder removably engagable with one of the plurality of notches on theperiphery of plate 68 in Fig. 12 for securing the shield 24 in any givenfastener spacing or eccentric position. This clamping. screw 74 hasprojecting therefrom and integrally formed therewith the ejection rod 65-in Figs. l and 10 for ejecting the spent cartridge case 23a from thebreech plug 56, asdescribed heretofore.

The shield 24 is resiliently biased toward the left in Fig. 1 so as tomove on the barrel 22 and within the outer tube 54. Helical shieldspring 26 is telescoped over the barrel 22 to not only bias the breechassembly 19 toward the first or safety position lin Fig. l but also urgethe ilash shield 24 against the workpiece intowhich the fastener is tobe driven. Stop means on the barrel muzzle on the left in Fig. l abutsagainst or is eifective upon the left end of the spring and comprises athread protector barrel cap 75 screwed onto the barrel muzzle and havinga slightly larger outside diameter than the barrel for arresting the.

leftward movement of the shield 24 and shield tube 70 located betweenthe spring 26 and the thread protector capV 75. The right end of thespring 26 in Fig. l is effective upon the collar or stop ring 51, whichtelescopes over the face on-workpiece 25. The thread protector cap 75 onthel barrel in Fig. 1 serves by abutting stop engagementas a means forpreventing the flash shield from traveling in a direction away from thebarrel breech beyond an approximately flush position with respect to thebarrel muzzle.V

and thus limit the eifective travel of spring 26.

The flash shield 24 for any given spacing adjustment is non-rotatablymounted with respect to a unit comprising the barrel 22 and the' outertube 54, but may be selectively indexed with respect thereto so that theadjustment indicia thereon in Fig. l2 will always be in the bestworkable position for view by the tool operator. are provided fordetachably connecting the shield tube 70 at any one of several spacedarcuate intervals within the outer tube 54. This comprises a bracket 77in Fig. 11 welded in a notch in outer tube 54 and extending inwardly soas to provide a flat across one side of the cylindrical bore of outertube 54. The shield tube 70 has a polygonal peripheral cross sectiontelescoped into the circumscribing cylindrical bore of the outer tube 54to restrain it against appreciable lateral movementas the flat orprojection on bracket 77 engages one of the polygon sides on the shieldtube 70, in the present disclosure a regular hexagonal outer surface, toprevent relative rotation between the tubes 54 and 70. Barrel 22 andshield tube 70 cannot appreciably rotate relative to each other becausebarrel guide screw 53, fixed in outer tube 54, restrains the barrelagainst rotation as it travels in barrel slot 22a, 22b. It should now beclearly apparent that the thread protector barrel cap 75 can beunscrewed from the muzzle of the barrel 22 so that the shield tube 70can be withdrawn from the bore yof outer tube 54 and then reinserted` inone of the six possible positions before reassembling the threadprotector cap 75 so that the indicia on plate 68 and thereference markson the shield 24 will be in Vtheir bestworkable position for easy viewing by the tool operator.

AThe barrel 22 has a plurality of ports 22d therein irnmediately behinda fully driven fastener for gas escape from the barrel bore. Althoughthe portholes should be each of bore diameter for best performance indiverting I 7oiture acts somewhat like a silencer, etc. `ThisV takes thethe gases, each porthole is made a slightly smaller diam-1 eter than thebarrel bore so as to retain the wad material from cartridge case 23a inthe bore. However, each porthole is funneled outwardly in a conicalshape (Fig. l1),

. to give a larger diameter and freer gas flow at the outside of thebarrel. As shown in Fig. 1l, these portholes are spaced at 120intervals. The portholes should not be located closer to the breech ormuzzle than is necessary. Their location relative to the muzzle isdetermined by the length of the fastener 23b remaining in the barrel 22after firing. The portholes are symmetrically spaced radially around thebarrel to provide a balanced force from the gas jets emerging from theports.

A satisfactory construction has been obtained with the followingdimensions. It should be clearly understood, however, that thesedimensions are merely illustrative and not limiting in any sense. Therst porthole 22a' on the left in Fig. 1 is approximately 7/a inch fromthe muzzle while the others are located at 5%; intervals. The bore ofbarrel 22 is approximately 1A inch while its outside diameter is about.79l inch. Each porthole is made by drilling and counter-sinking with aNo. 1 E.R. centering drill until the largest diameter of the countersinkis approximately .300 inch. Then, the hot gases are diverted from thebore after they have given the fastener the necessary velocity so thatthe surplus gases do not bypass the fastener to strike the workpiece 25to spall and to burn it.

After the surplus gas emerges from the ports'22d it travels to the rightin Fig. l between the outer surface of the barrel 22 and the bore ofshield tube 70, around the right end of shield tube 7 0 in Fig. l, andoutwardly toward the left between the outer surface of the shield tubeand the'bore of the outer tube 54 to strike against the back of plate 68to force the shield 24 firmly against the workpiece 25 beforeescapingradially outwardly past the open end on the left of outer tube54. Hence, the five flats on the outer surface of the shield-tube 70 inFig. 11 coact v with the circumscribing boreof outer tube 54 to permitthe shield tube 70, and increase the gas velocity (because`4 of thesmall cross sectional area of each space) so that the gas jets strikethe plate 68 at high velocitywith substantial force equally distributedaround the barrel bore so as to force the shield rmly and uniformlyagainst the workpiece 25.

The exhaust gases not only rmly drive the shield 24 against theworkpiece 25 and hold the barrel 22 against the workpiece by pushingagainst shoulder 70a in shield tube 70 and against plate 68, but alsoreduce the recoil of the tool. The angle atwhichports ,are placedrelative to the center line of the bore has a material effect on recoilreduction. This reduction in recoil is borne out by use' of the actualtool.

Since the exhaust gases travel through and between the Some tooloperators may attempt to improperly use the i tool Without flash shield24 and spring 26. Since it is a1- ways desirable for safety reasons touse the safety ash shield 24 and its spring 26 so as to use the toolproperly, means has been provided to prevent the ring of the tool unlessthey are used. This is a safety feature protecting the tool operatorprimarily against ricochets and incidentally against damage to his eardrums because this strucform in the present disclosure of a barrelengageable latching means located between the stop ring or collar 51 inFigs. 1 and 7 and the right end of shieldspring 2,6. A split annulargripper member serves as a lock or latch 'I adapted to engage in thegroove 22e on the periphery of*v the barrel with an annular C-shapespring 81 biasing these members inwardly and tending to force the splitgripper portions closed or into engagement with this groove 22e. In thelatching position, the location of these split gripper portions andgroove is such that if they are permitted to engage the groove in thebarrel, forward movement of the collar 51 relative to the barrel 22 isstopped after a predetermined point so that the collar 51 preventsfurther movement to the ring pin cocking position. The bore of thegripper portions on the left in Figs. l and 7 is con'- structed in theform of a female cone with its large end to the left. A barrel lockrelease 82, annular in form, has a male cone surface on the rightdesigned to mate and cooperate with the female cone previouslydescribed. This barrel lock release 82 is driven axially toward theright by spring 26 when the tool is properly used with the flash shield24 and spring 26 so as to hold the gripper portions 80 out of latchingengagement with the barrel groove 22e so as to keep the barrel gripperportions 80 in the unlatching position during normal usage. However,when the shield 24 and spring 26 are removed, there is no springpressure against barrel lock release 82. Therefore, the annular spring81 resiliently pulls the gripper portions 80 inwardly into engagementwith the barrel surface so that they will engage in the groove 22e assoon as the tool is moved sufficiently toward the ready-to-re position.Hence, the latching means would be in its latching position, beingbiased thereto by the spring 81, for preventing tiring of the tool ifshield 24 and spring 26 are eliminated and the tool is not properlyused.

When the fastener 23b is to be driven into a depression on the surfaceof the workpiece, such as in workpiece 25 in Fig. 15, the barrel muzzlemust during firing extend out beyond the flush relationship with the endof the flash shield 24 shown in Fig. 2. Since the tool, as illustratedin Fig. 2, could not be used for this type of job because the protrudingbarrel will not be moved back into the housing far enough to cock thefiring pin, a barrel extension 84 in Fig. 15 is generally used and hasfemale and male thread portions on opposite ends for detachableconnection between the muzzle of the barrel 22 and the thread protectorbarrel cap 75. Then, the firing pin and depressible pawl will beproperly aligned with the trigger for liring when the tool parts aremoved to the ready-to-fire position shown in Figs. 15, correspondingwith Fig. 2.

A storage recess is provided in the pistol grip handle 20 o'f the toolfor receiving when not in use the barrel extension 84 or any other typetool attachment desired. This storage recess or bore 20d in Fig. l isalso provided with a locking means for detachably locking the barrelextension 84 therein. This locking means comprises a o'ne-piece, ilatresilient spring latch 89 frictionally and detachably secured in arecess 20e in the pistol grip handle 20 extending inwardly from thebottom of the pistol grip in the same manner and direction as the bore20d. The latch has a mid-portion 89a, substantially flat, bearingagainst the bore side of the recess 20e, an attachment retainer portion89h on one end resiliently biased over the open lower end of the bore20d but swingable away therefrom for removal of the barrel extension,and its opposite end 89e bent back upon the mid-portion 89a with a sharpdistal end engaged in the recess side remote from the bore 20d. Thedistal end of portion 39h is rolled into a loop rotatably secur` ing aring 90'for manual manipulation of latch 89.

Within the handle bore 29d is also stored a disk adapter 86 for use inplace of the thread protector cap 75 in either Figs. 1 or 15. This diskadapter has a sleeve 86a having internal sleeve-like cap 75 with aspring 87 with a generally annular portion resiliently engagedinaperipheralf gro'ove of sleeve 36a and adapted to resiliently hold a-at,circular metallic disk pierceable by the fastener 23b as it emerges fromthe barrel muzzle 12 and before it enters the workpiece 25 or 25' so asto limit the penetration of the fastener 23h therein.

As mentioned before, the surrounding housing 21 and ring means 28 can bemoved endwise relative to barrel 22 in Fig. 1 by pressing the barrelmuzzle against the wo'rkpiece 25 so that the tool will move from anormal, muzzle advanced, safety position in Fig. 1 to a second, muzzledepressed ready-to-fire or ring position in Fig. 2. However, springs 26and 38 in Fig. 1 normally urge or bias the barrel 22 toward the rstposition shown in Fig. 1. Comparison of Figs. 1 and 2 will also revealthat the housing 21 and firing means 28 move relative to or advancetoward the ash shield 24 when moving from the rst position to the secondposition. Under some conditio'ns, it is desirable to limit this approachmovement so that they will never get together closer than apredetermined distance.

The structure for limiting or `blocking the movement of the housing 21relative to ash shield 24 includes the previously `described brackets 77and 52 in Fig. 1 with both having counter bores therein for receivingthe opposite ends of the tube 91. The bracket 77 on the left in Fig. 1is xed to the outer tube 54 of the housing 21 while the hinge bracket 52on the right is removably secured thereto for assembly by the barrelguide screw 53. A hollow extension Irod is telescopically mounted withinthis tube 91. This rod 95 is formed from seamless tubing, has a threadedoutside surface and an axial through bore With the seamless tubingconstruction providing the bore without the necessity of deep-drilling.The extension rod or screw 95 is counterbored from the right end in Fig.1 and a bushing 96 is inserted therein. This bushing 96 travels on aguide rod 92 anchored at its right end by a generally C-shape retainersnapped into a peripheral groove thereon. A compression spring 94 islocated between the retainer 93 and bushing 96 so as to keep theretainer 93 in proper position located against the hinge bracket 52while also urging the bushing 96 and extension screw rod 95 toward theleft in Fig. 1. The threads on the outer surface of the extension screwrod 95 may be of the American Standard form and have coacting therewithcorresponding threads on a release button 97 in Figs. 1 and 1l serving`as a nut when engaged with the rod 95 but movable in a direction normalto the rod 95. An elongated hole contains the screw threads in therelease button and straddles the extension screw rod 95, as more readilyseen in Fig. 1l. Less than onehalf of the circumference of thiselongated hole is threaded while remaining portion (lower portion inFigs. 1 and 11) is relieved for clearance during release buttonmovement. The button 97 has its threaded bore portion spring loadedagainst the extension rod 95. When the bottom of the release button 97in Figs. l and ll is pushed upwardly in Figs. 1 and 11 by manuallyexerted pressure, the threaded portions will dsengage to allow theextension rod 95 to move toward the left in Fig. 1 under the pressure ofspring 94. When the release button 97 is nol longer depressed, thepressure of spring 98 moves it downwardly in Figs. 1 and 11 to causethread engagement and to thus lock the extension rod 95 in whateveraxial location it has assumed at that time.

A downwardly projecting stop shoulder 95a on the right end of extensionrod 95 is adapted'to engage an upwardly extending stop shoulder 77a onthe supporting bracket 77 on the left in Fig. 1 when the extension rod95 is fully extended to prevent the escape of the extension rod 95during changing or indexing of flash shield 24 if button 97 should beaccidentally depressed. A flat is milled on the bottom of the extensionrod 95 in Fig. 1l since the threads on the lower side are never used.The portion projecting labove the at provides the stop shoulder 95a andthe top of the stop shoulder 77a coacts with the at to` prevent rotationof the extension rod 95 so that the 13 threads thereon are `alwaysfacing upwardly foi the proper coaction with the threads of the releasebutton 97.

It should b e noted that the barrel guide. screw 53 in Fig. 1 ispeculiarly located to provide a multiplicity of functions. It isthreaded into the outer tube collar 51 to secure said collar to theouter tube 54 and the hinge bracket 52. The hinge bracket 52 is thusremovable from the tools so that the extension rod tube 91 and the mul.-tiplicity of parts therein can be disassembled from the tool even thoughthe front tube supporting bracket 77 is lixed to the outer tube 54.Also, the upper tip end of the screw 53 in Fig. 1 travels in the barrelguide slots 22a, y2211 to prevent rotation of the barrel 22 relative tothe housing while permitting telescopic movement therebetween. Thisstructure provides easy assembly and servicing of the tool parts byauthorized personnel.

When the tool is used in the manner shown in Figs. l and 2 and it isconstructed without the barrel extension 84, the extension rod 95 andits associated parts are used as a safety locking means to preventmoving the tool housing relative to the barrel 22 to the ready-to-reposition in Fig. 2. The tool is normally manipulated by two handoperation necessitated by this safety locking means. One hand grips thepistol grip 20 with the nger in the trigger guard in front of thetrigger 46, as on a conventional gun, while the other hand surrounds theouter housing of the barrel assembly with one iinger, prefera bly theindex finger, engaging the outer surface of the t release button 97 todepress it into the outer housing. It Shoud be noted that the outerhousing, extension rod tube, and its supporting brackets are all encasedwithin a rubber or plastic sleeve grip 99 except for the exposed releasebutton 97, as seen in Figs. l, 2, 6, 9 and l1, for,

ease of operation and for appearance. It can be readily be seen thatreleasing or manually depressing the button 97 will make the safetyoperative or inoperative respectively to lock againstl or to permitaxial movement of the extension rod 95. If the button 97 is alwaysdepressed when the tool is being operated in two hand operations, theextension rod 95 will always extend forwardly toward the left in Fig. 1into contact with the ilash shield. Then, since the button 97 is held inthe safety inoperative or depressed position, the tool housing ispermitted to travel the full distance toward the readyto-re or tiringposition in Fig. 2 in the normal manner. However, release of the button97 will move the safety locking means to its operative position toprevent the tool. from traveling further toward the ready-to-fire orringposition if the tool parts are intermediate between the Fig. l and 2positions at the time of button release.

Then, the extension rod 95 will engage the back of the flash shield tospace apart the housing and tiring means 28 carried thereby from the ashshield 24 so as to stop the relative approach movement of the ash shieldand housing so that the pressing of the barrel muzzle against theworkpiece 25 cannot move the tool to the ready-tofire or firing positionin Fig. 2. This construction makes v necessary two hand operation of thetool by constantly blocklng the tool movement to the ready-to-tire oriiring position except when the button 97 is depressed.

Of course, the tool can be fired by one hand operation or Withoutcontinuously depressing button 97 Then, ex-

tension rod 95 is kept retracted within tube 91, as shown zle and ashshield 24 will be firmly against the Work-v piece'25' when the fastener231) is driven and also permits angle re control, the latter to bediscussed in more detail hereinafter.

However, the operator must set rod` 95 in a predetermined positiondependent upon the work;

1.4 piece depression depth; The operator depresses the re' lease button97 and 'pushes the barrel muzzle and flash shield 24 against theworkpiece 25 with the barrel axis extending generally perpendicular tothe fastener receiving surface of the workpiece. Then, the tool operatorreleases button 97 and never touches it again as long Vas theY same sizeworkpieces 25 are having fasteners driventherein, in other words,workpieces having the same depression depth. Now, when the tool is used,the flash shield 24 will always be, depressed firmly against theworkpiece and angle ire control can be utilized so that the tool canonly be tired if it is properly oriented with the workpiece.

Although the tool has basically the same angle tire control with orwithout bar-rel extension 84, angle re control can be most clearlyexplained by referring rst to Figs. l, 2, 9 and 14 wherein the tool isused without the barrel extension 84. A comparison of Figs. 2 and 14will reveal that merely making contact of the flash shield 24 and barrelmuzzle with the workpiece surface is not suicient to move the tool tothe ready-to-re or tiring position since housing tube 54 and shield 24act as stop means in Fig. 14 to prematurely arrest the movement. Thebore of barrel 22 must be approximately perpendicular to the surface ofworkpiece 25 in order to move the firing pin pawl 42 into alignment withthe trigger sear 46a. Squeezing the trigger 46 in Fig. 14 will never rethe tool' since both spring 35 and 38 bias barrel 22 and housing awayfrom the ready-to-re or firing position while pushing the barrel muzzleagainst the workpiece (spring 26 only pushes flash shield 24 against theworkpiece but does not urge the barrel because flash shield 24 does notengage the barrel cap 75). bore axis cannot be tilted substantially fromthe normal to the workpiece surface if firing is desired, the maximumpermissible tilt here to have so called approximately perricochet,spalling, or splattering of the workpiece mate; v

rial. Also, if the iring'pin 34 is released after thetrigger is pulled,the tool operator can be sure that the tiring pin tip has traveledsuciently far to the left in Fig. .2 to strike the primer of cartridgecase 23a. A failure to fire `therefore can be blamed only on a dudcartridge case.

It should be noted that Vthe back of tiring pin 34 has an extension vrod34a formed integralv therewith and slidably inan aperture in the back ofthe receiver housing 20a. The top or distal end of this rod extension34a in Fig. 2 is painted a contrasting color so that it is easilyvisible when it emerges Iat 4the mouth of the hole in the housing inresponse to the relative movement of the tiring pin and barrel to theready-to-lire position of Fig. 2 toA serve as a combination tilt andready-tore position indicator since i-t is not visible when the tool isin the safety position of Fig. l or when it is tilted excessively, as inFig. 14. When the tool is Acorrectly aligned and is in the ready-to-iireposition, the tip of the rod 34a is approximately llush with the housingouter surface, as shown in Fig. 2. This construction enables theoperator to determine before pressing the trigger that the tool is inits ready-to-re position, to prevent dud shots with the tool out ofposition, and to require holding the tool generally square with thesurface of the workpiece 25.

When the barrel extension 84 is used, the angle re control takes placeinsubstantially the same manner except that the extended rod in Fig. 15,after being set in the aforedescribed predetermined positioncorresponding to the depression depth in workpiece 25', acts as a stopmeans (instead of the stop means formed by the Hence, the barrel leftend of the barrel housing 50 in Figs. 2 and 14) for engagement with theback of the flash shield 24. Hence, this stop means rod 95, flash shield24 and barrel muzzle in Fig. 15 must be so located that when the flashshield 24 and the stop rod 95 are engaged and when the ash shield 24 andbarrel muzzle are pressed against and into engagement with theworkpiece, the barrel core must be approximately perpendicular to theworkpiece fastener receiving surface in order to `move the firing pin 34into the ready-to-re position in Fig. 15 with the trigger sear 46a andfiring pin pawl 42 aligned. The adjustability of extension rod 95assures that the left end of the rod 95 in Fig. 15 will be located atany predetermined distance ahead of the housing 50 for determining thestopping point of the shield 24 to correspond with the depth of thedepression in the workpiece 25'. Hence, the extension rod 95, whenproperly positioned, will assure that both the barrel muzzle and flashshield 24 are properly against the workpiece before the tool can befired. The barrel will be approximately perpendicular to the workpiecesurface, the left face of shield 24 in Fig. 15 will be approximatelyparallel to the surface it contacts, and the barrel muzzle will belocated sufficiently far from the left face of shield 24 in Fig. 15 toallow for the depression in workpiece 25. The variation fromperpendicular and parallel must be within the maximum tilt angle in eachcase. Of course, the maximum tilt angle (corresponding to the previouslymentioned 12 tilt) will be determined by the contacting engagementlocation between shield 24 and workpiece 25 as well as the length ofextension of stop rod 95; changing the extended length of rod 95 permitsselection of this maximum tilt angle within fixed limits.

Although the barrel' extension 84 in Fig. 15 is only illustrated asbeing used when driving fasteners into a depression on the workpiece, itshould be clearly understood that this barrel extension along with theangle fire control along with the tilt and ready-to-fire positionindicator 34a maybe used even with a workpiece having a flat surface,such as shown by workpiece 25 in Fig.- 2. Then, spring 26 urges flashshield 24 over the barrel extension into flush relationship with cap 75,as shown in Fig. 1, when the tool is removed from the workpiece. Theadjustability of the extension rod 95 permits the rod to be extended sothat the barrel muzzle and flash Shield 24 must be substantially flush(with flash shield 24 telescoped over extension 84) when they contactthe workpiece before the toolV can be fired. In other words, theextension rod 95 is extended from outer tube 54 and bracket 77 adistance equal to the length of the extension barrel 84 in thissituation.

The barrel extension 84 may also be used with a flat workpiece 25 whenan extra long fastener is being driven so that portholes 22d are sure tobe uncovered for gas release. The barrel extension adds a substantialdistance between the barrel muzzle and the porthole nearest thereto.

When the workpiece 25 is located at any given height from the floor, thepossibility of using the tool either with or without a barrel extension84 permits making the tool of convenient length. Then, the operator canconveniently grasp hand grip 20 and use the tool Without assuming anawkward or uncomfortable position.

The operational sequence in tiring a tool should now.

be quite clear. Grasp the sleeve grip 99 in Fig. 1 in one hand with onefinger pressing the release button 97 and grasp the hand grip 20 in theother hand. Locate the tool accurately on the workpiece by the referencemarks near the periphery of the flash shield 24 in Fig. 12 and thendepress the tool firmly and squarely against the workpiece. Check thefiring pin indicator 34a to be sure that its tip is generally flushwithk the housing so that the tool is in the ready-to-fre positionwithout excessive tilt from the normal to the workpiece surface. Nowpull trigger 46 to` fire the, tool. After firing, coul@ tinue to depressthe safety release button 97 as the tool is withdrawn' from theworkpiece so that the safety will be automatically operative on releaseof said button.

Figs. 16 and 17 illustrate a modified form of bayonet or connectingmeans between the barrel assembly and the breech assembly and moreespecially between the housings 27 and 50 thereof. In Figs. 1 and 8 ofthe previously described construction, a pair of overlatching pins 63,63 are admitted into a locking groove 511) by a pair of clearance flats51a. In Figs. 16 and 17, four circumferentially spaced inwardly orradially extending lugs 63' are formed integrally with a modified firingmechanism housing 30 in place of the overlatching pins 63 of Fig. 1.These lugs 63' in Figs. 16 and 17, all lying in a single planetransverse to the barrel axis bore, are held when the tool assembliesare locked axially behind correspondingly circumferentially spaced lugs51h extending outwardly from and formed integral with a modified outertube collar 51. This locked position is illustrated in Figs. 16 and 17.Adequate arcuate spacing is provided between each pair of adjacent lugsso that they can slip past each other after the one-eighth rotationunlocking turn has been made to move them from axial alignment of lockedposition to 45 arcuate spacing of unlocked position. This arcuateclearing spacing in Fig. 17 corresponds with the flat 51a in Fig. 8 forpermitting the removal of overlatching pin 63. `It should be noted thatthe lug segments 51h and 63 in Fig. 17 generally correspond in angulararcuate extent and in axial alignment with the thread segments 22t and37t of Fig. 5 on the barrel 22 and breech lock 37. The interlock pin 66in Figs. 6, 7 and 8 slides into the cutout formed by the spacing betweenthe axially aligned lugs 51b and 63 of Figs. 16 and 17 in their lockedpositions when the barrel is in its ready-to-re position, in the fullylocked tool position of Fig. 17. The other parts operate in basicallythe same manner as before.

Figs. 18 and 19 illustrate a modified thread form on the surface ofextension rod pictured in Fig. 1. The modified thread form on modifiedextension rod in Fig. 18 is of the buttress form thread with a verticalface at the right with a modified release button 97 having threads of acorresponding mating type on its segment 97a' in Fig. 19 making about a20 contact on the rod thread periphery while the remainder of the buttonbore is relieved for clearance. The pressure of the rod spring 94 inFig. 1 is balanced against the release button spring 98 so that the rodspring 9'4 is capable of continually driving the extension rod 95 towardthe left since the left face of each thread in Fig. 18, slanted upwardlytoward the right, permitting overriding of the mating threads on the rod95 and button 97 until the left end of the extension rod' 95 engages theback of the ash shield. Hence, the safety rod is always extended in itssafety operative position without requiring the operator to alwaysdepress the release button 97 However, when the flash shield 24 andbarrel muzzle are pressed against the workpiece to move the tool to theready-to-fire position in Fig. 2, the extension rod 95 will notautomatically move toward the right in Fig. 18 since this movement isresisted by engagement of the normal or vertical right faces of theextension rod threads with the corresponding thread faces on thethreaded segment 97a'. Hence, the release button 97 must be depressed inorder to move the tool to the ready-to-re or firing position.

Although the many features of this tool have been described withreference to only a cooking of the ring pin occurring when the tool ismoved to the Fig. 2 position so that the firing pin is in theready-to-fre position, it should be readily understood that many of thefeatures of this tool could also be used if the housing movementrelative to the barrel causes automatically not only the cooking butalso the release of the ring pin to explode the charge in the cartridgecase 23a as soon as the tool reaches the Fig. 2 position. Then, the Fig.2 position would properly be termed the tiring position. Although thismode of operation is generally not as desirable as the mode of operationdescribed heretofore because it is not as safe, it should be clearlyunderstood that the inventive concepts that have been described withreference to the present tool could also be used in a tool not havingthe ready-toire position.

Various changes in details and arrangements of parts can be made by oneskilled in the art without departing from the spirit of this inventionor the scope of the appended claims. v

What we claim is:

l. In a tool for explosively driving tfasteners into a surface,comprising a barrel through which the fastener is driven by a powderactuated charge, a deilector pad shield telescopically mounted over saidbanrel with the shield at the barrel muzzle, said shield including anadjustable gauge with rotatable indicia thereon -for aligning the toolfor any desired Afastener spacing, and means detachably connecting saidshield and barrel at spaced arcuate intervals so as to position theindicia in the best work able position and including means preventingrelative rotation at each interval between said shield and barrel.

2. In a tool for explosively driving fasteners into a surface,comprising a barrel through which the fastener is driven by a powderactuated charge, a housing tube surrounding but spaced from said barrel,a dellector .pad shield with a rearwardly extending tube, said shieldand shield tube telescopically mounted over said barrel with the shieldat the barrel muzzle and the shield tube telescoped into said housingtube, said shield including an adjustable gauge with rotatable indiciathereon for aligning the ltool for any desired fastener spacing, andmeans detachably connecting said shield and barrel at spaced arcuateintervals so as to position the indicia in the best workable positionand including means preventing relative rotation at each intervalbetween said shield and barrel, said last mentioned means comprising apolygonal cross sectional outer surface on said shield tube telescopedinto a circumscribing cylindrical bore in said housing tube having aprojection therein for engaging one of said polygon sides.

3. In a tool :for explosively driving fasteners into a surface,comprising a barrel through which the -fastener is 18 driven by a powderactuated charge, a housing tube sur; rounding but spaced from saidbarrel with one end open, a detlector pad shield with a rearwardlyextending tube, said shield and shield tube telescopically mounted oversaid barrel with the shield at the barrel muzzle and the shield tubetelescoped through said open end into said housing tube, said shieldincluding an adjustable gauge with indicia thereon for aligning the toollfor any desired fastener spacing, and means detachably connecting saidshield and barrel atl spaced arcuate intervals so as to position theindicia in the best workable position, and including means preventingrelative rotation at each interval between said shield and barrel, saidbarrel having port means therein immediately behind a fully drivenfastener for gas escape, said gas escaping out between said shield tubeand housing tube and between said shield and housing tube open end.

4. In a tool for explosively driving fasteners into a surface,comprising a barrel through which the yfastener is driven by a powderactuated charge, a housing tube surrounding but spaced from said barrelwith one end open, a deector pad shield with a rearwardly extendingtube, said shield'and shield tube telescopically mounted over saidbarrel with the shield at the barrel muzzle and the shield tubetelescoped through said open end into said housing tube, said shieldincluding an adjustable gauge with indicia thereon for aligning the toolfor any desired fastener spacing, and means detachably connecting saidshield and barrel at spaced arcuate intervals so as to position theindicia in the best workable position and including means preventingrelative rotation at each interval between said shield and barrel, saidlast mentioned means comprising a polygonal cross sectional outersurface on said shield tube telescoped into a circumscribing cylindricalbore in said housing tube having a projection therein for engaging oneof said polygon sides, said'barrel having port means therein immediatelybehind a fully driven fastener for gas escape, said gas escaping outbetween said shield tube and housing tube and between tube open end.

No references cited.

